1. Field of the Invention
This invention relates to an improved process for producing hydrogen peroxide by directly contacting hydrogen and oxygen in the presence of a metal catalyst and in the optional presence of a stabilizer. According to the process herein, hydrogen and oxygen are contacted in the presence of a catalyst and a multifunctional phosphonate or phosphate preparation, in the presence of halide ions and acid, to make hydrogen peroxide. The use of such preparations in the process results in a decrease in catalyst deactivation.
2. Technical Background
Various processes for making hydrogen peroxide by means of the direct combination of oxygen and hydrogen, in the presence of a catalyst, are known. U.S. Pat. No. 3,336,112, for example, discloses a process for the direct production of hydrogen peroxide comprising contacting a mixture of gases containing oxygen and hydrogen with a solid catalyst having a metallic component selected from the group consisting of metals in Group VIII of the Periodic Table, in the presence of a liquid containing water and a stabilizer. "Sequestrative" hydrogen peroxide stabilizers, including phosphoric acids, are used. For this purpose, phosphonate polymers containing two or more acid phosphonate groups are preferably used.
U.S. Pat. No. 4,009,252 discloses a process for preparing hydrogen peroxide by reacting hydrogen and oxygen in an aqueous medium containing a platinum group catalyst characterized in that the partial pressure of hydrogen and the partial pressure of oxygen are maintained at at least 0.5 atmosphere and at least 1.0 atmosphere respectively, and the platinum group catalyst is caused to be present in an amount, calculated as a metal, of at least a minimum effective catalyst amount up to 30 mg per 100 ml. of said aqueous medium.
U.S. Pat. No. 3,470,243 claims tetrakis (dihydrogen phosphono methyl) ethylene diamine, N,N'-dioxide. These organo-phosphono-amine oxides have been found to be be especially effective sequestering agents for metal ions in alkaline mediums.
U.S. Pat. No. 3,383,174 claims an aqueous hydrogen peroxide solution stabilized against decomposition by contaminants containing a nitrilo trimethylene phosphonic acid compound and a tin compound soluble in aqueous hydrogen peroxide.
U.S. Pat. No. 4,070,442 discloses stabilization of aqueous hydrogen peroxide solutions by phosphonic acid stabilizers (Dequest 2000.RTM.and Dequest 2010.RTM.).
The present discovery improves upon the art by providing an additive that decreases catalyst deactivation. This object, and other objects and advantages, will be described in the below description of the invention, examples and claims.